Those aren't the type of goods these companies are making. All of these companies have durable market power (in search, networking/communication, marketplaces);

Those aren't the type of goods these companies are making. All of these companies have durable market power (in search, networking/communication, marketplaces); and can and have used it to expand their own power like the article says, and do it at the expense of smaller competitors. Hence the new anti-rust view being one that stops such anti-competitive actions.